The present invention relates to an internal combustion engine, which comprises an intake system including a carburetor having a throttle valve, a distributor and an ignition timing regulating device connected to the distributor.
In an internal combustion engine, it is desirable to retard the ignition timing during its low speed driving condition so as to reduce the noxious content, such as, CO, HC and NO.sub.x in the engine exhaust gases. During a high speed driving condition, however, it is desirable to advance the ignition timing so as to increase the output power.
If, on the other hand, the ignition timing is retarded upon deceleration from a high speed driving condition, it is possible to strengthen the braking effect on the engine.